[Protective air bags in traffic accidents. Change in the injury pattern and reduction in the severity of injuries]

[Secondarily accelerated foreign bodies as a source of danger from airbag deployment]

BACKGROUND

The use of airbag systems in motor vehicle construction has led to a significant reduction in both the frequency and intensity of injuries during traffic accidents. However, recent reports have shown numerous cases in which it is assumed that the airbag was the major cause of serious injury.

CASE REPORT

In a collision with a wild boar, both airbags in the automobile deployed. The driver suffered facial abrasion and belt contusion to the left shoulder. The passenger held a glass bottle in her hands during the impact that, secondarily accelerated through the airbag, hit both eyes and the bridge of her nose. On clinical admission, the patient showed fractures of the nasal bridge, of both medial orbital walls on both sides and a massive periocular haematoma which required direct examination under narcosis. Both eyes showed an orbital contusion, a large area of corneal abrasion, traumatic mydriasis with sphincter tears such as bilateral 90% hyphema. During surveillance, a progressive reduction in visual acuity occurred. After posterior chamber vitrectomy with epiretinal peeling and posterior chamber lens implantation in the left eye, visual acuity was 0.05 in the left eye and 0.01 in the right.

CONCLUSIONS

A considerable danger emanates from objects which are situated between head and airbag in the moment of airbag deployment. This requires public education and, in addition, airbag systems which are adapted to the drivers height and weight, as well as to objects in its immediate vicinity.

The Effects of Depowered Airbags on Skin Injuries in Frontal Automobile Crashes

The purpose of this study was to determine the effects of depowered frontal airbags on the incidence of skin injuries. The National Automotive Sampling System database files from 1993 to 2000 were examined in a study including 2,246,524 occupants exposed to airbag deployment in the United States. There was no significant difference between full-powered and depowered airbags, with 60.2 percent of those exposed to a full-powered deployment sustaining a skin injury versus 59.5 percent of occupants exposed to a depowered airbag (p = 0.19). Whether occupants were exposed to a full-powered airbag (1,936,485 occupants) or a depowered airbay (310,039 occupants), the majority of skin injuries were to the upper extremity and the face. Regardless of airbag power, the overwhelming majority of the skin injuries were minor (99.8 percent). There was not a significantly greater risk of injury from any source for occupants exposed to a depowered airbag or a full-powered airbag (p = 0.87). The data suggest that the implementation of depowered airbags did not affect the number, seriousness, location, or source of skin injuries.

Correlation of head injury to vehicle contact points using crash injury research and engineering network data

Head injury is the most common cause of morbidity and mortality in motor vehicle crashes. Efforts to improve vehicle design, which minimize forces exerted to the occupant's head, may lead to a reduction in the frequency and severity of head injury. We therefore set out to identify mechanisms producing severe head injury in motor vehicle crashes (MVC) derived from the crash injury research and engineering network (CIREN) database. CIREN combines crash site analysis, vehicle damage assessment, and occupant kinematics in relation to the occupant's injuries. From the Seattle CIREN database of 101 cases, compiled from 1997 to 1998, we selected those crashes in which the occupant sustained severe head injury (abbreviated injury score, AIS>or=4) for analysis. We examined crash mechanism, energy transfer, point of head contact, vehicle intrusion and resulting injuries. There were 15 cases with severe head injury. These were primarily due to side impacts (n=10) in comparison to front impacts (n=5). The average net change in velocity (delta velocity, DV) was 15 mile/h (range 4-29 mile/h). In cases where the primary point of head contact could be elucidated the B-pillar predominated (4 cases, 33.3%) followed by the striking external object (2 cases, 16.7%), A- (1 case, 8.3%) and C- (1 case, 8.3%) pillars, roof side rail (1 case, 8.3%), windshield header (1 case, 8.3%), windowsill (1 case, 8.3%) and airbag (1 case, 8.3%). In this series the predominant mechanism of head injury was lateral impacts, especially those in which the victims' heads struck the B-pillar. The need for improved head protection from lateral impacts is indicated.

Foot fractures in restrained front seat car occupants: a long-term study over twenty-three years

OBJECTIVES

To analyze the mechanism of injury for foot and ankle fractures resulting from automobile accidents to create a basis for developing an improved design for protection.

DESIGN

Retrospective.

SETTING

Level I trauma center with accident research unit.

PATIENTS

Automobile accident reports and medical records of individuals injured in the accidents.

MAIN OUTCOME MEASUREMENTS

Technical indicators (collision type, impulse angle, deltav, and extent of vehicle deformation) and clinical data (injury location and severity [abbreviated injury scale and injury severity score] and long-term outcome).

RESULTS

From 1973 to 1996, 15,559 car accidents were analyzed. Two hundred sixty-one front seat occupants sustained fractures of the foot and ankle (ankle, 41 percent; forefoot, 29 percent; midfoot, 20 percent; and hindfoot, 10 percent). Seventy-five percent of the fractures were classified abbreviated injury scale(foot) 2. The incidence, location, and abbreviated injury scale(foot) category of fractures were similar between driver (n = 210) and front seat passenger (n = 51). Fifty percent of the fractures occurred in head-on collisions and 34 percent occurred in accidents with multiple collisions. The deltav ranged in 82 percent of car crashes between fifteen and sixty kilometers per hour. The deltav and extent of foot compartment deformation correlated with the abbreviated injury scale. During our investigation, deltav increased; the injury severity score decreased; and the extent of deformation did not differ significantly.

CONCLUSIONS

Although overall car passenger safety has improved, the relative incidence of foot and ankle fractures has increased. Comparing drivers and front seat passengers, the foot pedals, steering wheel, or the asymmetric design of the dashboard did not influence injury incidence, mechanism, or severity. Foot fractures are mainly caused by the foot compartment deformation in head-on collisions, and therefore improvements in foot compartments are essential for fracture prevention.

Injuries of the pelvic ring in road traffic accidents: a medical and technical analysis

Between 1985 and 1995, 9380 traffic accidents occurring in the area of Hannover, Germany, were analysed; 12428 individuals had been injured and 387 (3.1%) had sustained a pelvic-ring injury (AIS(PELVIS)>2). In 131 cases (34%), the injuries were further classified (Pennal and Tile) and a technical reconstruction made of the accident: 52% were type A, 27% type B and 21% type C injuries; 46% were in cars, 12% on motorised two-wheelers, 10% on bicycles and 1% in utility vehicles; 31% were pedestrians. Pelvic-ring injuries occurred in restrained vehicle occupants in accidents with a (delta)V of more than 30 km/h, whereas they occurred in a considerable proportion of unrestrained vehicle occupants, pedestrians and bicyclists at lower (delta)V or collision speed. The percentage of B- and C-type injuries increased in crashes with higher (delta)v or collision speed. In addition to further improvements of the passive safety, lower collision speeds or (delta)V would reduce or prevent pelvic-ring injuries. Due to the small number of occupants protected by airbags in this study, their protective effect for the pelvis could not be assessed. The reconstruction of pelvic-ring injury mechanism in traffic accidents is possible when technical and medical factors are considered.